from __future__ import print_function

from math import sqrt

try:
    xrange  # Python 2
except NameError:
    xrange = range  # Python 3


def is_prime(n):
    for i in xrange(2, int(sqrt(n)) + 1):
        if n % i == 0:
            return False

    return True


def sum_of_primes(n):
    if n > 2:
        sumOfPrimes = 2
    else:
        return 0

    for i in xrange(3, n, 2):
        if is_prime(i):
            sumOfPrimes += i

    return sumOfPrimes


if __name__ == '__main__':
    import sys

    if len(sys.argv) == 1:
        print(sum_of_primes(2000000))
    else:
        try:
            n = int(sys.argv[1])
            print(sum_of_primes(n))
        except ValueError:
            print('Invalid entry - please enter a number.')
